Yahoo Map of Battle of Taranto, 11th November 1940

The naval Battle of Taranto took place on the night of 11 November – 12 November 1940 during World War II. The Royal Navy launched the first all-aircraft naval battle in history, flying a small number of aircraft from a single aircraft carrier in the Mediterranean and attacking the Italian fleet at Taranto. Britain won the battle in what pundits around the world saw as the end of the "big gun" ship and the rise of naval air power.

In 1939 Italian operations in North Africa, centered on Libya, required resupply from the Italian mainland. British North African operations, centered in Egypt, suffered from much greater supply difficulties, convoys having to cross the entire Mediterranean Sea from depots in Gibraltar. This put the Italian fleet into an excellent position to cut off supplies to the British forces.

In repeated actions the Royal Navy had always come out on top, considerably upsetting the Mediterranean balance of power. So instead of direct action, the Italians left their ships safely in harbor, leaving the mere threat of a sortie to cause the British serious problems. This exemplified the theory of a fleet in being. At the time this "fleet-in-being" was fairly powerful, the harbor at Taranto contained six battleships (although one was not battle-worthy), seven heavy cruisers and two light cruisers, and eight destroyers.

The British, upset with the potential for an attack on their lifelines, had long ago drawn up Operation Judgement, the surprise attack on Taranto. For this mission they sent the new HMS Illustrious to join HMS Eagle in Admiral Andrew Cunningham's fleet. They had originally intended to launch it on 21 October 1940, Trafalgar Day, but damage to both carriers prevented this, and Illustrious took on planes from Eagle and launched the attack alone. The task force consisted of Illustrious, two heavy cruisers, two light cruisers and four destroyers.

Several reconnaissance flights by Martin bombers operating from Malta had confirmed the existence of the Italian fleet, but to make sure the British also sent in a Short Sunderland on the night of November 11, just as the task force was forming up about 170 miles away from the harbor, just off the Greek island of Cephalonia. This let the Italian forces know that something was happening, although without radar there was little they could do but wait.

The first wave of 12 Fairey Swordfish torpedo bombers left the Illustrious just before 21:00, followed by a second wave of 9 aircraft about an hour later. The first wave approached the harbor at 22:58 and split into two groups, one attacking the ships in the outer harbor (Mar Grande) and a smaller group flying over the town to the inner harbor (Mar Piccolo). The second wave attacked from the northwest over the town about an hour later. During the attacks the battleship Littorio took hits from three torpedoes, while the battleships Conte di Cavour and Caio Duilio were both hit by one each, while a cruiser in the inner harbor had been damaged by bombs. The planes had dropped flares in order to see their targets at night, and although this also gave gunners on the ground better visibility, the Italians shot down only two of the Swordfish.

The Italian fleet suffered a mortal wound, and the next day transferred its undamaged ships to naval bases farther north in order to protect them from similar attacks in the future. Repairs to Littorio took about four months and to Caio Duilio, six, but Conte di Cavour required extensive salvage work and its repairs remained incomplete when Italy left the war in 1943. The Italian fleet lost half its strength in one night, the "fleet-in-being" no longer existed, and the Royal Navy took uncontested control of the Mediterranean.

Even with this serious blow, the Italian fleet had the resources to take part within a month in the battle of Cape Spartivento (27 November 1940) with good results. However the British decisively beat the remaining Italian fleet a few months later during the battle of Cape Matapan (March 1941).

Air launched topedo experts in all modern Navies had previously thought that torpedo attacks against ships required deep water, at least 100 ft (30 m). Taranto had a water depth of only 40 ft (12 m). However the Royal Navy used modified torpedoes, and also dropped them from a very low height. This aspect of the raid, and others, served as an important input for the planning of the Japanese attack on Pearl Harbor. Japanese planning staff studied it intensively.